'Inside Llewyn Davis': Oscar Isaac, Marcus Mumford, and the Punch Brothers perform a song from the film -- EXCLUSIVE VIDEO

The star of the upcoming Coen brothers film Inside Llewyn Davis may be the dark, handsome, and somewhat mysterious Oscar Isaac, but the soul of the film is its music – a folk-inspired soundtrack featuring some of the biggest names in music, including Justin Timberlake. Isaac is featured on several of the tracks, which he performs himself in the film as the titular down-on-his-luck songsmith Llewyn Davis. To celebrate the film, the producers staged a concert in New York with folk geniuses the Punch Brothers (literally – band leader Chris Thile won a MacArthur Genius Award in 2012) and filmed the event for an upcoming Showtime special. The Punch Brothers were joined by Isaac and Mumford & Sons frontman Marcus Mumford (who associate produced the soundtrack) on “Fare Thee Well,” which you can listen to in an exclusive clip below.

Veteran music producer T Bone Burnett executive-produced the album, his second for the Coen brothers – the O Brother, Where Art Thou soundtrack was released to great acclaim when that movie came out back in 2000.

Another Day/Another Time: Celebrating the Music of “Inside Llewyn Davis” airs on Showtime, Dec. 13, at 10 p.m. The film, Inside Llewyn Davis, comes out in theaters on Dec. 6.